docs-desktop/dotnet-desktop-guide/framework/winforms/advanced/graphics-paths-in-gdi.md

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Graphics Paths in GDI+	03/30/2017	csharp vb	graphics [Windows Forms], paths GDI+, drawing paths paths [Windows Forms], drawing drawing [Windows Forms], paths	a5500dec-666c-41fd-9da3-2169dd89c5eb

Graphics Paths in GDI+

Paths are formed by combining lines, rectangles, and simple curves. Recall from the Vector Graphics Overview that the following basic building blocks have proven to be the most useful for drawing pictures:

• Lines

• Rectangles

• Ellipses

• Arcs

• Polygons

• Cardinal splines

• Bézier splines

In GDI+, the xref:System.Drawing.Drawing2D.GraphicsPath object allows you to collect a sequence of these building blocks into a single unit. The entire sequence of lines, rectangles, polygons, and curves can then be drawn with one call to the xref:System.Drawing.Graphics.DrawPath%2A method of the xref:System.Drawing.Graphics class. The following illustration shows a path created by combining a line, an arc, a Bézier spline, and a cardinal spline.

Using a Path

The xref:System.Drawing.Drawing2D.GraphicsPath class provides the following methods for creating a sequence of items to be drawn: xref:System.Drawing.Drawing2D.GraphicsPath.AddLine%2A, xref:System.Drawing.Drawing2D.GraphicsPath.AddRectangle%2A, xref:System.Drawing.Drawing2D.GraphicsPath.AddEllipse%2A, xref:System.Drawing.Drawing2D.GraphicsPath.AddArc%2A, xref:System.Drawing.Drawing2D.GraphicsPath.AddPolygon%2A, xref:System.Drawing.Drawing2D.GraphicsPath.AddCurve%2A (for cardinal splines), and xref:System.Drawing.Drawing2D.GraphicsPath.AddBezier%2A. Each of these methods is overloaded; that is, each method supports several different parameter lists. For example, one variation of the xref:System.Drawing.Drawing2D.GraphicsPath.AddLine%2A method receives four integers, and another variation of the xref:System.Drawing.Drawing2D.GraphicsPath.AddLine%2A method receives two xref:System.Drawing.Point objects.

The methods for adding lines, rectangles, and Bézier splines to a path have plural companion methods that add several items to the path in a single call: xref:System.Drawing.Drawing2D.GraphicsPath.AddLines%2A, xref:System.Drawing.Drawing2D.GraphicsPath.AddRectangles%2A, and xref:System.Drawing.Drawing2D.GraphicsPath.AddBeziers%2A. Also, the xref:System.Drawing.Drawing2D.GraphicsPath.AddCurve%2A and xref:System.Drawing.Drawing2D.GraphicsPath.AddArc%2A methods have companion methods, xref:System.Drawing.Drawing2D.GraphicsPath.AddClosedCurve%2A and xref:System.Drawing.Drawing2D.GraphicsPath.AddPie%2A, that add a closed curve or pie to the path.

To draw a path, you need a xref:System.Drawing.Graphics object, a xref:System.Drawing.Pen object, and a xref:System.Drawing.Drawing2D.GraphicsPath object. The xref:System.Drawing.Graphics object provides the xref:System.Drawing.Graphics.DrawPath%2A method, and the xref:System.Drawing.Pen object stores attributes, such as width and color, of the line used to render the path. The xref:System.Drawing.Drawing2D.GraphicsPath object stores the sequence of lines and curves that make up the path. The xref:System.Drawing.Pen object and the xref:System.Drawing.Drawing2D.GraphicsPath object are passed as arguments to the xref:System.Drawing.Graphics.DrawPath%2A method. The following example draws a path that consists of a line, an ellipse, and a Bézier spline:

[!code-csharpLinesCurvesAndShapes#101] [!code-vbLinesCurvesAndShapes#101]

The following illustration shows the path.

In addition to adding lines, rectangles, and curves to a path, you can add paths to a path. This allows you to combine existing paths to form large, complex paths.

[!code-csharpLinesCurvesAndShapes#102] [!code-vbLinesCurvesAndShapes#102]

There are two other items you can add to a path: strings and pies. A pie is a portion of the interior of an ellipse. The following example creates a path from an arc, a cardinal spline, a string, and a pie:

[!code-csharpLinesCurvesAndShapes#103] [!code-vbLinesCurvesAndShapes#103]

The following illustration shows the path. Note that a path does not have to be connected; the arc, cardinal spline, string, and pie are separated.

See also

• xref:System.Drawing.Drawing2D.GraphicsPath?displayProperty=nameWithType
• xref:System.Drawing.Point?displayProperty=nameWithType
• Lines, Curves, and Shapes
• How to: Create Graphics Objects for Drawing
• Constructing and Drawing Paths